Testing asynchronous circuits: A survey

Asynchronous circuit design has been studied for decades, but it has only recently been feasible to construct large and e cient asynchronous systems. This paper surveys di erent techniques for checking whether an asynchronous circuit has fabrication defects. The inherent di erences between asynchronous and synchronous circuits, primarily that asynchronous circuits do not have a global clock, necessitate a review of the testing techniques used for synchronous circuits and a re-evaluation of the trade-o s involved. New methods that e ciently utilize the structure of asynchronous circuits are possible, most notably self-checking asynchronous circuits can be implemented with little or no circuit overhead.